1. Filed of the Invention
The present invention relates to a display of three-dimensional image, and specifically, to a method of forming pixel-cell for three-dimensional image display.
2. Description of the Related Technology
Generally, since men can see three-dimensional images within only a viewing zone, so an optical apparatus must be needed to form the viewing zone, which forms two viewing zones. One is distributed at a predetermined distance from the front of image display panel. The other is distributed at only predetermined region in front of image display panel. In general, contact-type three-dimensional image display method corresponds to the former, and projection-type image display method corresponds to the latter.
A contact-type full parallax three-dimensional image display apparatus uses an image display panel and one or two special optical plate(s) which is(are) overlapped on the image display panel for division of multiple viewpoint image and for forming the viewing zone. But since optical elements of the optical plates or pixels of the image display panel are arranged in periodic pattern, Moire pattern appears due to the overlap of optical plates and deteriorates the displayed images. Since Moire pattern is a natural phenomenon produced due to the interference between those repetitive patterns (e.g., stripe pattern) of overlapped optical plates or sheets it is impossible to eliminate the Moire pattern completely by any physical means.
The angle between patterns of two or more overlapping optical plates is generally about 90° or ±45° to form the full parallax three-dimensional image, and at this angle, the effect of the Moire phenomenon is very high. But a period of Moire patterns is varied according to the angle between patterns. Therefore, by adjusting the directions of arrangement of optical plates which are overlapped on/below the image display panel from the direction of pixel arrangement of the image display panel, it's possible to make the period of Moire pattern at a region where three-dimensional image is viewed to be below the resolution of viewer's eye. Therefore, the Moire pattern effect is decreased.
To implement a full parallax-type three-dimensional image display apparatus, it is needed to arrange multiple-view images on the image display panel in a unit of pixel cell having identical shape and size. Furthermore, it is needed for each optical element of optical plates which are overlapped on the image display panel to expand corresponding pixel cell and to be overlapped exactly at one spatial position for forming viewing zone. To do so, it is necessary to vary the shape of the pixel cell according to the arrangement directions of optical plates, and especially in order to satisfy the latter condition it is preferred that all pixel cells have the same shape and size. Furthermore, it is preferred that the pixel cells are arranged without gap on the image display panel.
However, in conventional flat display apparatus including LCD(Liquid Crystal Display) as used image display panel, square-type pixels are arranged in checker board pattern, wherein the pixel is a unit element for displaying image in image display panel. It is preferred that the pixel cell for three-dimensional image display comprises two or more pixels.
However, in case of forming rhombus-type pixel cell having an arbitrary vertex angle besides square or rectangular pixel cell, some pixels may be divided by sides of rhombus-type pixel cell and the divided pixel may be inserted into two or more different pixel cells. Because the pixels located along sides of rhombus-type pixel cell are inserted into two or more different pixel cells, positions of divided pixels in a viewing zone are different. Thus the resolution of a three-dimensional image is deteriorated.